If I want to use BioMag particles, do I have to buy a QIAGEN magnet too or can I use one that I already have?

For maximum performance, BioMag particles should be used with one of QIAGEN magnets. Since BioMag particles are so small, they require a strong magnetic field in order to separate them in a timely fashion. The BioMag magnets are rare earth (Neodymium-Iron-Boron) magnets embedded into plastic, with magnetic strengths ranging from 27 megagauss Oersteds to 35 megagauss Oersteds depending on the magnet. Strong magnets from alternative suppliers may also provide a suitable alternative.